Assembly of apparatuses for implementing data transmission via the human body

ABSTRACT

A set of a first apparatus and a second apparatus that are secured to a garment, each of which includes an electrical signal processor unit connected to a first terminal and to a second terminal. At least the second terminal faces an inside surface of the garment, the processor units and the terminals being arranged to perform data transmission between the two apparatuses by establishing at least one wireless connection between the first terminals of the two apparatuses.

FIELD OF THE INVENTION

The present invention relates to a method of conveying data between two electronic apparatuses carried or worn by at least one user.

The invention also relates to a set of at least two apparatuses for implementing the method.

BACKGROUND OF THE INVENTION

Progress in electronics and computing, miniaturization of components, and increased battery lifetime are making it possible for certain professionals, such as soldiers, to be fitted with electronic apparatuses or devices that provide them with assistance in accomplishing their missions. Such electronic apparatuses include, in non-limiting manner, a display device housed in a helmet and enabling close-up viewing and/or viewing in poor light, a communications unit having a transceiver associated with a microphone and an earphone, a computer for recording and/or consulting information, a telescopic sight mounted on a weapon, . . . . These various apparatuses are connected to one another, e.g. so that images coming from the sight or the display device can be sent to the computer for storage therein and/or to the transceiver for transmitting to a command center. Similarly, it is appropriate for the electrical signals issued by a keypad or by any control situated on an apparatus to be received and executed by another apparatus situated at a certain distance from the first. The apparatuses are fixed or inserted in pockets at various locations of a soldier's garments, and also on a helmet, a weapon, etc.

The apparatuses are connected to one another via cables that may present a total length of several meters and a weight of several kilograms. These cables are integrated as thoroughly as possible in the garment, however they project beyond it (e.g. the cable going to the helmet or to the weapon) and they run the risk of catching on obstacles during movements performed by the soldier. In addition, movements or falls of the soldier may lead to traction, twisting, or shear forces being exerted both on the cables and on the connectors that connect them to the apparatuses. The connectors run the risk of being dirtied by mud or sand and they must be leaktight whether or not they are connected in order to ensure that moisture cannot establish electrical leaks and lead to the contact of the connectors being destroyed by electrolysis. Measures for protecting cables and connectors, such as incorporating them in a garment and providing leaktight caps, increase the weight of the garment as well as its cost. The connections also constitute unreliable zones of weakness that might endanger a mission.

Proposals have been made to replace at least some of the wire connections by wireless connections, and more particularly by radio connections such as those complying with the IEEE 802 standard. Nevertheless, such radio connections present drawbacks:

-   -   they can be detected, intercepted, and/or jammed; and     -   they rely on antennas that present directivity, particularly         since they are close to the body, and also polarization         sensitivity that may prevent data being transmitted when the         soldier is in certain positions.

Infrared wireless connections have also been proposed, however they do not provide significant improvements in the above-mentioned drawbacks.

SUMMARY OF THE INVENTION

An object of the invention is to propose means enabling signals to be transmitted while minimizing any recourse to wired connections and while providing improvements concerning the above-mentioned drawbacks, at least in part.

According to the invention, there is provided a set of at least a first apparatus and a second apparatus that are secured to a garment, each of which includes an electrical signal processor unit connected to a first terminal and to a second terminal, at least the second terminal facing an inside surface of the garment. The processor units and the terminals are arranged to perform data transmission between the two apparatuses by establishing at least one wireless connection between the first terminals of the two apparatuses.

In a first embodiment, and assuming that the desired transmission distance is short (a few centimeters to one meter), the solution proposed makes use of an electric field (also referred to as a near field or a non-formed field) for transmitting data. Unlike the electromagnetic waves used in the radio solution, only an electric field is created by the surface of any conductor that is raised to a voltage. If this voltage is modulated, the field is also modulated and the modulation is transmitted to another conductor of non-zero area, which other conductor then constitutes the second plate of a capacitor.

Thus, in the first embodiment, the first terminal and the second terminal comprise a first electrically conductive plate and a second electrically conductive plate that are arranged to establish a first connection and a second connection with the other apparatus so as to form a circuit for transmitting data between the apparatuses, the first connection making use of at least one external capacitive coupling and the processor units of the apparatuses being arranged:

-   -   from the first apparatus, to introduce a signal into the circuit         for transmitting an electrical signal, which signal corresponds         to data for transmission, such that the signal passes in the         form of a field in the first connection; and     -   in the second apparatus, to receive the signal and process it in         order to recover the data.

Since the distance between the apparatuses is small, being limited to the dimensions of the body of the user, the conductive areas may be of arbitrary shape, providing their dimensions are small compared with the greatest expected transmission distance. Electric fields can be transmitted even if the surface areas extend in planes that are perpendicular. This is particularly advantageous given that electric field transmission is insensitive to corrosion, since the conductive surfaces may be covered in an insulating coating. The term “external” capacitive coupling is used to mean that the capacitive coupling is established outside the apparatus, in the “open air”, and not inside an electronic component.

The electrical signal may be a direct current (DC) signal or an alternating current (AC) signal, and it may be a control signal or a data signal. By way of example, the signal may be modulated in order to transmit data and the field is thus itself modulated in corresponding manner. Simple demodulation in the second apparatus thus makes it possible, after picking up the electrical signal, amplifying it, and possibly shaping it, to recover the data contained therein.

In the second embodiment, the terminals face an inner surface of the garment and the processor units of the apparatuses are arranged:

-   -   from the first apparatus, to introduce an electrical signal into         the body of a wearer of the garment, which electrical signal         corresponds to the data in such a manner as to create a         potential field in the body of the wearer; and     -   at the terminals of the second apparatus, to receive the signal         and process it in order to recover the data.

Thus, it is the body that constitutes the vector via which the signal is transmitted by conveying the potential field to the second apparatus. The terminals of the apparatuses are pressed against or stuck directly to the skin of the user and they enable the electrical signal to be introduced into the user's body by conduction or by capacitive coupling. In practice, when the conductive electrodes are pressed against or stuck to the user's skin, the conduction and capacitive coupling modes of introducing the signal through the skin take place simultaneously and they complement each other. The electrical signal may be a DC signal or an AC signal and it may be a signal for powering the apparatus, a control signal, or a data signal. By way of example, the signal may be modulated to transmit data, and the potential field is thus itself modulated in corresponding manner. Simple demodulation in the second apparatus thus makes it possible, after the electrical signal has been picked up, amplified, and optionally shaped, to recover the data contained therein.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention appear on reading the following description of particular, non-limiting embodiments of the invention.

Reference is made to the accompanying drawings, in which:

FIG. 1 is an elevation view of a set of apparatuses in accordance with a first embodiment of the invention;

FIG. 2 is a diagrammatic view showing the operating principle of a simplified version of this embodiment;

FIG. 3 is a cutaway diagrammatic perspective view of one of the apparatuses;

FIG. 4 is a fragmentary section view of a set in accordance with a first embodiment in position on a user's body;

FIG. 5 is a cutaway fragmentary plan view of a set in accordance with a variant of the first embodiment of the invention;

FIG. 6 is a cross-section view showing connection means for connecting apparatuses together in this variant; and

FIG. 7 is a view analogous to FIG. 1 showing a set of apparatuses in a second embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 to 3, the set of apparatuses in accordance with the first embodiment of the invention is integrated in a garment, given overall reference 1, in the form of a jacket to be worn by a soldier and including a plurality of pockets, some of which receive respective apparatuses. The apparatuses in this embodiment comprise a computer 3, a radio transceiver 4, and a telescopic sight 5 optionally secured to a weapon 6.

Each apparatus 3, 4 comprises a box 7 of electrically insulating material containing a processor unit 12 arranged to send and receive electrical signals carrying data and capable of extracting data from a received electrical signal. The box 7 has an outer bottom face covered by a plate 13 made of an electrically conductive material, and an outer top face covered in a layer of metal plating forming an electrically conductive plate 14. The plates 13 and 14 may be inside the box and/or they may be identical in structure. The plates need to be spaced apart from conductive portions such as integrated circuit boards of the processor unit in order to avoid capacitive overloading in transmission mode and a poor capacitive ratio in reception mode. If this is not possible while also maintaining small thickness for the box, then the plates need to be separate from the box (see the description of the sight 5) or need to be in the form of a frame surrounding the box.

The sight 5 comprises a box containing a processor unit connected to conductive plates 9 and 10 that are separate from the box and secured to grips 11 of the weapon.

Each of these apparatuses 3 and 4 is received in a respective pocket of the garment 1 such that the electrically conductive plate 13 faces an inside surface 8 of the garment 1 (with only the plate 13 of the computer 3 being shown).

The operation of the set of apparatuses is described below with respect to transmitting data, e.g. between the radio transceiver 4 and the computer 3.

The apparatuses 3 and 4 are connected in series by a first connection I and a second connection II so as to form a data transmission circuit between these two apparatuses. The connection I makes use of capacitive coupling. The connection II makes use of current conducted through the body H of the user.

The processor units are arranged to implement a data transmission method that comprises the steps of:

-   -   from one of the apparatuses, e.g. the radio transceiver 4,         introducing an electrical signal into the body of the user,         which signal corresponds to the data, e.g. sound (a so-called         “audio” analog signal, or a digital signal), in such a manner         that the signal passes via the connection II and thus through         the body of the user and via the connection I by capacitive         coupling between the plates 14; and     -   in another apparatus, e.g. the computer 3, receiving the signal         and processing it in order to extract data therefrom.

In this embodiment, the transmitted signal is an alternating signal modulated at a predetermined frequency, or else a digital signal, itself conveyed unaltered or after modulation. It is possible to provide for as many carrier frequencies or modulation types or optionally sequential modulation codes (time division multiple access (TDMA), code division multiple access (CDMA), digital subscriber line (DSL), for example) as there are apparatuses, in order to avoid interference between the signals and in order to select the destination apparatus for the signal by using on transmission the frequency or the coding means or the recognition means (multiplexing techniques) allocated to that apparatus.

The plates 13 are fastened to the inside face of the garment for those apparatuses that are carried by the garment.

When the plates 13 are directly in contact with the user's skin, an electrical contact is established between each plate 13 and the body of the user, such that the data signal is transmitted by conducting a current between the apparatuses via the user's body. When a garment layer, such as an undergarment or a lining of the garment 1, is interposed between the plates 13 and the skin, the garment layer does not impede transmission of the signal via the body between the apparatuses, since capacitive coupling is established between each apparatus and the body that enables signals to be transferred in the form of electric fields between each apparatus and the body, with the signals passing through the body by conduction in the form of current. It can thus be understood that several garment layers may be interposed between the plates and the user's body. When the intervening garment is dirty or wet (sweat, rain, crossing a ford), transmission is not degraded, on the contrary it is improved.

Provision may be made for the garment and the plates to be directly in contact with the user's skin, such as the plate 9 of the sight 5 that is in direct contact with the user's skin when the user is not wearing gloves, while the plate 10 is left uncovered for connection by capacitive coupling or by contact with an electrically conductive surface covering the skin or the garment for the purpose for transmitting the electrical signal both by conduction and by capacitive coupling. Signal transmission by conduction is particularly useful for DC signals or low frequency signals. Signal transmission by capacitive coupling is effective at higher frequencies and suffices when there is no need to convey a DC component.

In the variant of FIG. 4, the garment 1 includes an electrically conductive layer 16 that is in contact with the plates 14 of the apparatuses 3 and 4. By way of example, the conductive layer 16 comprises conductive particles embedded in the fabric of the garment, conductive fibers mixed with the fabric of the garment, or a conductive coating applied to the garment. The fabric is made conductive on being woven (by inserting conductive fibers), by being impregnated, or indeed by deposition (of particles or a coating). The connection I then serves to transmit the signal by conduction in the conductive layer, thus making it possible to limit signal attenuation, and by capacitive coupling via the interfaces between the conductive layers and the plates 14.

In the variant of FIG. 5, the garment 1 has a conductive layer made up of two strips 16.1 and 16.2 that are independent and that make up the connection I. The strips 16.1 and 16.2 make the following connections respectively:

-   -   the plate 14.1 of an apparatus 15 to the plate 14 of the         computer 3; and     -   the plate 14.2 of the apparatus 15 to the plate 14 of the radio         transceiver 4.

The connection II between the apparatuses 3 and 15 and the apparatuses 4 and 15 is of the same type as that described above. It is thus possible for communication to take place simultaneously between the apparatuses 3 and 4 and the apparatus 15.

FIG. 6 shows the strip 16.1 subdivided into two segments 16.1.a and 16.1.b that are suitable for being connected together via an electrically conductive press button having a portion 17.a secured to the segment 16.1.a and a portion 17.b secured to the segment 16.1.b. The press button may be used as a switch.

It is possible to envisage using other connection techniques, for example self-gripping elements under the trademark Velcro, zip fasteners, . . . .

With reference to FIG. 7, the set of apparatuses in the second embodiment of the invention, as in the first embodiment, is integrated in a garment given overall reference 1, the garment having a plurality of pockets, some of which receive respective apparatuses. In this embodiment, the apparatuses are a computer 3, a radio transceiver 4, and a telescopic sight 5 optionally secured to a weapon 6.

Each of the apparatuses 3 and 4 received in a pocket of the garment 1 has two terminals facing an inside surface 8 of the garment 1 (only the terminals 7 of the computer 3 are shown). The sight 5 is fitted with terminals 9 secured to grips 10 of the weapon 6. Each apparatus 3, 4, 5 has a processor unit (only the processor unit 11 of the computer 3 is shown) arranged to transmit and receive electrical signals carrying data and capable of extracting data from a received electrical signal.

The processor units are arranged to implement a method of conveying data that comprises the steps of:

-   -   from one of the apparatuses, e.g. the apparatus 5, introducing         an electrical signal into the user's body, the signal         corresponding to the data, e.g. an image (a so-called “video”         analog signal or a digital signal), so as to create a potential         field in the user's body; and     -   at the terminals of another one of the apparatuses, e.g. the         computer 3, receiving the potential field, recovering the         signal, and then extracting the data therefrom.

In this embodiment the transmitted signal is an alternating signal modulated at a predetermined frequency or a digital signal, itself conveyed as such or after being modulated. It is possible to provide as many carrier frequencies or types of modulation or optionally sequential modulation codes (e.g. TDMA, CDMA, DSL) as there are apparatuses so as to avoid interference between the signals or so as to select the destination apparatus for the signal by transmitting it at the frequency or using the coding or recognition means (multiplexing techniques) allocated to that apparatus.

Since the terminals are fastened to the inside face of the garment, for those apparatuses that are carried by the garment, and since a garment layer—such as an undergarment—is generally interposed between the terminals and the skin, the signal is easily transmitted between the body and the terminals of the apparatus by capacitive coupling. It can be understood that a plurality of garment layers may be interposed between the terminals and the user's body. When the interposed garment(s) is/are dirty or wet (sweat, rain, crossing a ford), transmission is not degraded, on the contrary it is improved since coupling by conduction is associated with the capacitive coupling that is itself not attenuated.

Provision may be made for the garment and the terminals to be in direct contact with the user's skin. Furthermore, the terminals of the sight 5 are in direct contact with the user's skin when the user is not wearing gloves. Under such circumstances, the electrical signal is thus conveyed both by conduction and by capacitive coupling. If the user is wearing insulating gloves, then coupling is capacitive only. In order to improve the conduction of the skin, it is possible to cover it in a conductive gel or a conductive paint. When gloves are worn, it is possible to make the fabric of the gloves conductive by various methods, if it is desired to have coupling by conduction. In general, coupling by conduction is useful for transmitting DC or low frequency signals. Capacitive coupling is effective for higher frequencies and suffices when there is no need to convey a DC component. The conduction component may also be improved by arranging the electrodes in zones of the human body that are naturally moist, such as the armpits or the mucous membranes. It can be understood that the potential field is conducted by the skin or by the flesh underlying the skin.

In a variant, when two users are wearing garments as described above, it is possible for signals to be transmitted from an apparatus of one of the users to an apparatus of the other user when the users are touching each either via two portions of their bodies, e.g. when they are holding each other by the hands, or else when they are holding by one hand only, while also making use of capacitive coupling between the feet and the ground, which is generally conductive, at least to some extent.

Naturally, the invention is not limited to the embodiments described but covers any variant coming within the ambit of the invention as defined by the claims.

In particular, although the invention is described in a military application, civilian applications can also be envisaged for establishing communication between electronic apparatuses carried by civilians, such as telephones, cameras, or media players.

The electrical signals may be of optionally modulated alternating type, or they may be alternating signals with a DC component, or they may be DC signals (in the second embodiment).

If the quality of the received signal is too poor, given firstly that its level needs to be limited on transmission to avoid any physiological discomfort (or indeed danger), and also given that it is subjected to attenuation and deformation in the body, it is possible to have recourse to various types of analog modulation, and in particular frequency modulation, single side band modulation, phase modulation, quadrature modulation, etc., and also to various kinds of digital modulation, the list thereof not being limiting either. Any known signal extraction technique may advantageously be used.

In the first embodiment, and if necessary, in order to reduce attenuation of the signal it is possible to increase the frequency at which it is conveyed, to use plates of greater area, or to reduce the capacitance that exists between the two plates (dedicated to the connections I and II respectively).

Signal processing in order to extract data therefrom may be digital or analog processing, possibly associated with corrections in the event of non-linearities and/or techniques for recovering lost data in the event of a high bit error rate (BER).

The signals may also be multiplexed.

The plates may be arranged on the flanks of the boxes.

The apparatuses may include a plurality of plates each dedicated to forming a connection II with another apparatus.

The two connections established between the apparatuses may make use of capacitive coupling, without conduction via the human body, in particular when the apparatuses are remote from the human body and more generally from an electrically conductive element. Naturally, the apparatuses must nevertheless be close enough to one another to enable capacitive coupling to be established.

Each connection may implement one or more capacitive couplings and/or one or more conductive couplings. 

1. A set of a first apparatus and a second apparatus that are secured to a garment, each of which includes an electrical signal processor unit connected to a first terminal and to a second terminal, at least the second terminal facing an inside surface of the garment, the processor units and the terminals being arranged to perform data transmission between the two apparatuses by establishing at least one wireless connection between the first terminals of the two apparatuses.
 2. The set according to claim 1, wherein the first terminal and the second terminal comprise a first electrically conductive plate and a second electrically conductive plate that are arranged to establish a first connection and a second connection with the other apparatus so as to form a circuit for transmitting data between the apparatuses, the first connection making use of at least one external capacitive coupling and the processor units of the apparatuses being arranged: from the first apparatus, to introduce a signal into the circuit for transmitting an electrical signal, which signal corresponds to data for transmission, such that the signal passes in the form of a field in the first connection; and in the second apparatus, to receive the signal and process it in order to recover the data.
 3. The set according to claim 2, wherein the apparatuses are arranged so that the second connection implements at least one capacitive coupling.
 4. The set according to claim 2, wherein the apparatuses so that the first connection (I) implements a plurality of capacitive couplings in series.
 5. The set according to claim 2, wherein the apparatuses are arranged so that the second connection implements conduction, the electrical signal corresponding to the data passing in the form of current in the second connection.
 6. The set according to claim 5, wherein the apparatuses are arranged so that the second connection passes via the body of the user.
 7. The set according to claim 6, wherein the apparatuses are arranged to establish electrical contact between each apparatus and the body of the user.
 8. The set according to claim 6, wherein the apparatuses are arranged to establish capacitive coupling between each apparatus and the body of the user.
 9. The set according to claim 6, wherein conduction takes place directly through the body of the user.
 10. The set according to claim 6, wherein conduction takes place via a conductor extending over the skin of the user.
 11. The set according to claim 2, wherein the first plates of the apparatuses face an inner layer of the garment, the inner layer being electrically conductive.
 12. The set according to claim 11, wherein the conductive inner layer comprises at least one of the following elements: an electrically conductive substance impregnating a portion of the garment; an electrically conductive substance sprayed onto a portion of the garment; electrically conductive fibers extending in a fabric of the garment; and an electrically conductive film fastened facing a portion of the garment.
 13. The set according to claim 2, wherein the garment includes a layer extending facing the second plates of the apparatuses.
 14. The set according to claim 2, including an apparatus secured to an article including a grip zone for being held in a hand of the user, and the second plate of the apparatus is fastened to the grip zone.
 15. The set according to claim 1, wherein the terminals face an inner surface of the garment and the processor units of the apparatuses are arranged: from the first apparatus, to introduce an electrical signal into the body of a wearer of the garment, which electrical signal corresponds to the data in such a manner as to create a potential field in the body of the wearer; and at the terminals of the second apparatus, to receive the signal and process it in order to recover the data.
 16. The set according to claim 15, wherein the signal is introduced or received via the terminals of the apparatuses by conduction with the skin of the wearer.
 17. The set according to claim 15, wherein the signal is introduced or received via the terminals of the apparatuses by capacitive coupling with the skin of the wearer.
 18. The set according to claim 15, wherein the signal is introduced or received via the terminals of the apparatuses both by conduction and by capacitive coupling.
 19. The set according to claim 15, wherein at least one of the apparatuses is secured to an article including a grip zone for each hand, and the terminals of the apparatus are fastened to respective ones of the grip zones. 